Centrifugal governor



Nov. 22, 1960 J. H. PARKS CENTRIFUGAL GOVERNOR Filed March 10, 1958 mmvrox JEHN H. PARKS TTORAEYS 2,961,229 CENTRIFUGAL GOVERNOR John H. Parks, Peoria, 111., assignor to Caterpillar Tractor-Co., *Peoria, 111., a corporation of California Filed Mar. 10, 1953, Ser. No. 720,372

form. (31. 73-513 The presentinv'ention relates generally to engine governors and specifically to a spring balanced mechanical governor having centrifugally actuated fiyweights for positioning the fuel control member of'an internal combustion engine.

One of the objects "of this invention is to provide a mechanical governor wherein the flyweights are rotated about the axis .of .a fuel control member with which is asociat'e'd a' c'oritrol leveroperable in'one direction to preload the governor-spring and operable in the opposite direction to engage andposition the fuel control member.

Another object of this invention is to provide a mechanical governor of the type described wherein the operating lever engages a rod associated with the fuel rack of an internal combustion engine in such a manner that the rack may be positioned to shut off the engine, as well as-at any operating setting, through a single control lever.

Still another object of this invention is in the formation of a lost motion connection between said control rod and rack bar constructed in such a manner as to reduce the mass rotating with the governor.

Another important object is to provide an adjustable low idle stop in the form of a peripheral cam formation on a threaded member which is rotatable to adjust the position of the cam.

Further and more specific objects and advantages of this invention are made apparent in the following specification wherein reference is made to the accompanying drawing.

In the drawing:

Fig. 1 is a longitudinal sectional view of a governor embodying the present invention with parts broken away to show the structural details thereof; and

Fig. 2 is a fragmentary sectional view in perspective illustrating the relationship between the operating lever and the low and high idle stops in the same governor.

Referring particularly to Fig l, the governor of the present invention is illustrated as comprising flyweights 11 pivotally mounted in a carrier 12 as by pins 13. Carrier 12 is pressed on a hub portion 14 of a pinion 16 in constant mesh with a drive gear 17 secured to a shaft 18 forming a part of the timing gear train of an engine. Pinion 16 is journalled for rotation on a stationary bushing 19 pressed into a wall 21 of the engine housing.

Flyweights 11 move outwardly under the influence of increasing engine speed to move a thrust member 22 to the left, as shown in Fig. 1, against the force of a governor spring 23. This axial movement of member 22 urges the fuel control member or engine rack bar 24 to the left through a connection comprising a pin 26 retained in the end of the bar 24 and secured within an adapter 27 which functions as one of the spring seats for the governor spring 23.

Axially aligned with the bar 24 is a control rod 28 slidably journalled within a hollow bearing support 29 pressed into the governor housing 30 as shown. A second spring seat 32 is slidably carried on the bearing 29.

A control lever assembly generally indicated 35 is pro- 2,961,229 "Patented Nov. 22, 1960 2 vided with two'bellcranklevers 36 and 37 joined together by'a'tuhular hub niember 38 which is fixed to a shaft 39 'rotatably journalled in the housing 30 Secured to the "end of shaft 39 is a lever 41 (see Fig. 2) which is manually'operable'either at the engine or through remote control linkage (not shown). Said linkage may be connected to lever 41 'at a hole '42 provided in the end of said lever to 'alter the preload setting on the governor spring 23 by pivotal movement of lever assembly 35. When the shaft39 is'rotated in a clockwise direction the preload on the' governorspring 23 is increased. By rotating the lever in a counterclockwise direction the rack bar24'may'be moved through the entire-operating range of the engine and may be positioned at the no-fuel position'to shut off the'engine as willsubsequently be de- 'rnoves 'the fuel control rack 24 to the fuel shutoff position indicated by broken'lines at '54.

Under normal engine operation after a governor s'pringipreload has been selected by the appropriate positioning 'of'lever assembly '35 rack bar 24 may oscillate @rially under'the influence of fiyweight forces unimpeded by the control rod 28 because of the lost motion link represented by the axial distance between the ends'56 and 5710f the control rodfand rack bar respectively. Under certain operating conditions in response to sudden surges in engine speed, the flyweight force may be sufficient to move the rack fast enough and far enough so as to cause the adapter 27 to strike the end of the bearing 29. As a protective measure and to reduce the shock under this condition a resilient member in the form of a Belleville spring 58 is loosely retained on the control rod 28 so as to absorb the shock in the event the adapter 27 moves far enough to strike the end of the bearing 29. On the other hand, when engine speed is suddenly reduced causing the fiyweights to collapse, rack bar 24 is moved toward the right under the influence of spring 23 to open the rack. If this change in engine speed is sudden enough plate 51 may be damaged when it strikes the wall of the governor housing 30. To prevent this damage a resilient stop in the form of a relatively stiff spring blade 59 is retained in appropriate location by fastening means 59a secured to the wall of housing 30.

To provide operator feel of the relative position of the control lever 35 in determining the governor setting, a low idle stop generally indicated 60 is in the form of a peripheral cam surface 61 on the shank of a threaded bolt 62. Bolt 62 is provided with a hexagonal head 63 and an enlarged diameter 64 which acts as a pilot in a suitable bore 66 in said housing. The other end of bolt 62 is threaded at 67 and engages a tapped hole provided in a lug 68 protruding from the wall within the housing 30.

The lever parts 36 and 37 of lever assembly 35 have tail portions 65 between which is secured a tubular member 69. Lever 36, is appropriately bored to receive a detent 71 contained in member 69 and urged outwardly of the lever assembly as by a captive spring 72, The nose '73 of the detent protrudes sufliciently to engage the cam 61 and is formed with a cone of an angle that substantially matches the angle of the low idle cam surface 76 on the cam 61.

Referring back to Fig. 1,, as the lever assembly 35 is rotated in a counterclockwise direction detent 71 traverses a path indicated by, the broken arcuate line 74 in such a'manner that at a selected position in its arcuate travel, f nose 73 of detent 71 contacts the inclined cam surface 76 thus indicating to the operator that the governor'is setat a low idle operating condition. Continued arcuate movement'of the lever in a counterclockwise direction will cause the detent to pass over the high point of the cam which will automatically force the lever to continue'on in a counterclockwise direction to position the rack bar 24 to the shutofi position under influence of the declining slope 77 of the low idle stop member 69 and the force of captive spring 72 behind detent 71. In order to position the cam precisely for appropriate engine performance, the relative position of the cam with respect to the arc of movement of the detent may be adjusted by threadably positioning the cam in the housing.

At the other end of the engine operating range, means is provided for adjustably setting a high idle stop which establishes the maximum speed range of the engine. To this end a threaded member 78 having an enlarged hexagon head 79 is threadably secured within a suitably tapped hole 81 in the governor housing 30. The position of the member 78 determines the maximum allowable degree of. clockwise rotation of lever assembly 35, since the end 82 presents an abutment which member 69 of lever assembly 35 contacts to define the high idle stop position.

The high idle stop 78 is located adjacent the low idle stop 60 so that once the relative positions for both said stops are established, a suitable locking cap 83 secured to housing 30'as by a capscrew 84 retains both stops in their selected positions by the registration of a pair of serrated sockets 86 formed in said cap with the hexagon heads 63 and 79 of stop members 60 and 78 respectively.

Under normal operating conditions the flyweight force urges pinion 16 axially to the right against a shoulder 4 19a of bushing 19. In order to retain the pinion 16 on bushing 19 in the absence of flyweight forces, as when the engine is idle, a snap ring 87 carried in an annular recess in the hub portion of pinion 16 is provided with an end 88 extending radially through a suitable hole in the hub 14 and into an annular recess 89 formed near the end of the bushing 19. Another function of snap ring 87 is to insure against separation-ofthe carrier 12 and the hub portion of the pinion 16 which would result in engine overspeeding if such a. condition should occur.

I claim:

In a spring balanced centrifugal type governor of the character described the combination with a control lever operable in one direction to load the spring and in the opposite direction to engage and move a fuel control member toward shut-down position, a spring loaded detent carried by the lever, a rod threaded for longitudinal adjustment having an enlarged portion positioned to be engaged by the detent to provide a low idle stop for said lever, said enlarged portion presenting a uniform profile coaxially circumscribing the rod and having an abrupt slope for engagement by the detent on one side and a gradual slope on the opposite side to provide more resistance to shut-down movement of the lever than to spring loading movement of the lever.

References Cited in the file of this patent UNITED STATES PATENTS 1,924,228 Bull Aug. 29, 1933 2,204,640 Woodward June 18, 1940 2,252,838 Drake et a1. Aug. 19, 1941 2,307,974 Turner Jan. 12, 1943 2,511,095 Barnes June 13, 1950 2,572,096 Baker Oct. 23, 1951 r 2,787,918 Dow Apr. 9, 1957 2,823,820 Merchant Feb. 18, 1958 FOREIGN PATENTS 896,406 France Apr. 24, 1944 926,101 Germany Apr. 7, 1955 

